In recent years, digitalization of image content such as movies or broadcast programs has been proceeding rapidly. As a result, digitalized image content has been distributed to an audience through digital broadcasting or Internet distribution. In this instance, as image content to be broadcasted or distributed, content in which image date and secondary data are previously and integrally included has been used. With reference to FIG. 1, a conventional distribution method for digital image content will be described. FIG. 1 is an explanatory view illustrating the procedure for preparing, distributing, and reproducing conventional digital content.
As shown in FIG. 1, image data 1 and secondary data 2 such as subtitles are superimposed together to prepare one image master 3. The secondary data 2 incorporated in this image master 3 is treated as image data. Next, the image master 3 is digitalized to prepare a digital master 4. This digital master 4 is a master file for the image content that is distributed through Internet and the like. The image content accommodated in the digital master 4 is reproduced at the receiver side, and is viewed as the digital image content 5.
When the conventional image content is distributed through Internet and the like, digital code is compressed and distributed at the transmitter side, and the compressed digital code is decrypted and reproduced at the receiver side. If the throughput capacity of the receiver side is relatively low, a problem arises in that missing frames and flickering of the subtitles occur at the same time.
Further, when a correction is necessary during the edit until the digital master 4 is prepared, the correcting operation causes a lot of difficulties. For example, if the secondary data requires a correction, the secondary data is firstly corrected, and subsequently, the image master 3 and the digital master 4 are prepared again.
Furthermore, subtitles or advertisements are often superimposed while a digital broadcasting program is on the air. This can be done by synthesizing the subtitles onto the image date at predetermined timings or by switching the image data to the advertisement data. In this instance, the subtitles or the airplay schedules of the advertisements are written on a program schedule table, which is so-called a “cue sheet”, and the predetermined subtitles or advertisements are broadcasted on schedule of the air time.
When sound of a foreign film is translated to prepare subtitles, subtitles are prepared for each translating word, and the edit is carried out by the same operation as above. In the aforementioned procedure of the edit, a great effort is required for each translating word, which indirectly discourages a production of multi-kinds of subtitles. Accordingly, in the conventional distribution method for digital image content, there is a drawback in that the operations from edit to distribution require a great effort and a lot of difficulties.